# set 集合 frozenset(不可变集合) 无序，不重复
# s = set("agcdee")
# s = set(['a','b','c','d','e'])
# s = {'a', 'b', 'c'}

# frozenset可以作为dict的key
s = frozenset("abc")

print(type(s))
print(s)

# 向set添加数据
another_set = set("cef")
re_set = s.difference(another_set)
re_set = s - another_set
print(re_set)
re_set = s & another_set
print(re_set)
re_set = s | another_set
print(re_set)

if "c" in re_set:
    print("i am in set")

print(s.issubset(re_set))